WORLD PIPELINES AUGUST 2006 www.worldpipelines.com 49

rmen Lange is the second largest gas field on the Norwegian

continental shelf, with estimated natural gas reserves of

400 billion m3. The production capacity of the field, which

is operated by Hydro, will reach 70 million m3/d, totalling

21 billion m3/yr. The gas will be transported by the Langeled pipeline from

Nyhamna on the north-west coast of Norway to Easington on the

north-east coast of England, via the Sleipner riser platform in the

North Sea. By connecting the pipeline systems through Sleipner,

there is the flexibility to send gas to the UK through the new

pipeline, as well as through existing pipelines to mainland Europe.

Gas from other fields in Norway could also be delivered

through the new connection.

Navigate the official website for

the Ormen Lange field and you will

find some interesting facts about

this mega-project.1 The Ormen

Lange field will be capable of sup-

plying up to 20% of the UK’s natural

gas demand. To understand how this

capacity will be achieved, it is helpful

to illustrate the dimensions of the

Langeled project with the following: in

comparison with some of the world’s

most remarkable engineering feats,

the pipe steel would weigh 15 times the

steel used in the Hoover Dam; the con-

crete would build 9 Toronto CN Towers;

and if the steel reinforcements were to

be unspooled, they would travel 1.3 times

around the Equator, constituting enough

material to build 2.3 Eiffel Towers.

A number of children at Easington

Primary, a school at the receiving end of the

pipeline, were told about the project and the

extent to which it would affect their future.

Naturally, they were curious. An intriguing

Figure 1. Loading out concrete coated pipe from Farsund.

Robert Buchanan, Canusa-CPS and Sean Haberer, Bredero Shaw, Canada,

describe the Langeled pipeline project and detail the pipe coating

applications used on the subsea gas pipeline.

50 WORLD PIPELINES AUGUST 2006 www.worldpipelines.com

question came from six year old Katy Steele, who asked, “How many sec-tions of pipe are there... and how long are they?”

The names Ormen Lange and Langeled, meaning 'giant serpent' and 'long connection' in Norwegian, hint at the response to this question: approximately 100 000 joints of 42 in. and 44 in. con-crete weight coated steel pipe comprise the export line, which will transport 21 billion m3 of gas annually. This will make Langeled the longest subsea pipeline in the world, snaking some 1200 km along the North Sea floor.

With a project of this magnitude it is especially important to have access to optimum pipeline production and laying resources. The construction and operation of Langeled is thus highly specialised, with Ormen Lange’s licensees (Hydro, Shell, Statoil, Dong, Exxon Mobil), as well as ConocoPhilips, assuming responsibility for different phases of the pipeline’s development.

The contract to coat the pipes was awarded to Bredero Shaw, a division of ShawCor Ltd., and was signed in Farsund, Norway on 12th December 2003. The first pipes were received in

April 2004 and thereafter began the process-ing of 100 000 pipes, according to Statoil and Norsk Hydro’s specifications. The steps included loading in and storage of pipe; inter-nal flow efficiency coating to improve the gas flow in the pipeline; external asphalt-based corrosion resistant coating; concrete weight coating to sink the pipe down to the sea floor, curing of the concrete and finally storing and loading out of the coated pipe. In total, more than one million tonnes of steel pipe, one mil-lion tonnes of concrete and 25 000 tonnes of steel reinforcements went through Bredero Shaw’s Farsund plant during the coating opera-tions for Langeled.

A major logistical challenge for Bredero Shaw was accommodating the great number of pipes that arrived on a continual basis. The Farsund facility has storage area for approximately 33 000 pipes of 42 in. and 44 in. at a time. That left a storage deficit for approximately 67 000 of the Langeled-destined pipes. This challenge was solved by

transporting the coated pipes to intermediate storage loca-tions near to where the pipes were to be laid. Four interme-diate storage locations were acquired for this project: Hartlepool in the UK (28 000 pipes) for the southern part; and Måløy (20 300 pipes), Kristiansund (2800 pipes) and Bergen (8900 pipes) in Norway for the northern sec-tion of Langeled. To date, 1 200 000 lifts of pipes and 430 000 transport movements have been car-ried out and 673 vessels have helped in the cargo movement at Farsund.

By late July 2004, the delivery of the 44 in. coated pipes to the field had begun allowing the pipe laying to begin on schedule.

Installation of the corrosion protective field joint systems is one of the last operations prior to letting the pipe off the pipelay vessel. Canusa-CPS, ShawCor’s field joint corrosion protection products division, was contracted to supply all of the corrosion-resistant, heat-shrinkable sleeves to the pipelay contractors. Canusa-CPS qualified a relatively new heat-shrinkable sleeve product for the project, called MIS-65. This product was developed specifically for concrete weight-coated offshore pipelines and meets the requirements of many major project specifications, such as the DNV RP F-102 and Statoil TR-1109. The advantages of using heat-shrinkable sleeves were that the product was supplied as one piece per joint, which made estimating simple. The product could also

Figure 2. Storage of uncoated pipe in Farsund.

Figure 3. Application of MIS-65 heat-shrinkable

sleeve.

WORLD PIPELINES AUGUST 2006 www.worldpipelines.com 51

be applied very quickly using the pipelay contractor’s own crew members. These factors kept costs down and gave project scheduling control over to the pipelay contractor’s own people.

Acergy, based in the UK, and Allseas, from the Netherlands, are using Acergy’s Piper and Allseas’ Solitaire, two of the world’s largest pipelay vessels, to perform the major work of the project.

Canusa provided full support throughout the Langeled contractor’s on-board pre-qualification phase and provided application training on start-up, despite both contractors having substantial experience with heat-shrinkable sleeve systems. During a typical application, the joint was cleaned with a power wire brush to the specified cleanliness level and then pre-heated using either electrical induction coils or propane torches. The sleeves were then wrapped around the joint and heat-shrunk using a propane torch with the installa-tion process taking less than four minutes (excluding surface preparation) per joint. After installation of the field joint corro-sion protection, subcontractors supervised installation of an infill system to level the gap created by the cutback in the concrete weight coating.

For field-applied girth weld joints, heat-shrinkable sleeves are the most common offshore joint protection system in the industry, providing superior corrosion protection for pipelines operating up to 130 ˚C. The use of heat-shrinkable sleeves is so readily accepted due to their unique combination of repeatable procedure and proven performance attributes. Application and design specific heat-shrinkable sleeves need to be considered in all cases since the adhesive provides sleeve adhesion and corrosion protection, and a tough, cross-linked polyolefin backing must be resistant to the potentially high installation temperatures of the infill system materials or abrasion and shear forces for non-concrete weight coated pipelines.

The coating of the 44 in. pipes in the southern part of the pipeline was completed in 2005 and the gas is scheduled to begin flowing this year. The coating of the northern part of the pipeline was completed in March 2006 and pipelaying opera-tion began 1st April 2006. Langeled will be ready to transport gas when the Ormen Lange field starts up in October 2007. The MIS-65 heat-shrinkable sleeve has allowed the contrac-tor to meet or exceed their installation target.

http://www.ormenlange.com/1.

Figure 4. Completed heat-shrinkable sleeve on the lay barge.